1. Technical Field
The present invention relates to a web product cutting and screening machine and method for cutting and screening folded or stacked web products.
2. Description of the Prior Art
Commercial toilet paper products, subject to their packing method, can be classified into interfold toilet paper (pop-up toilet paper) type, stacked toilet paper (flat pack toilet paper) type, and toilet paper roll type. Consumers can select toilet paper products subject to their habits or needs.
The processing or fabrication of toilet tissue paper varies with toilet tissue paper stacking status. FIG. 1 illustrates a conventional web product cutting machine. As illustrated, this conventional web product cutting machine 10 comprises a first conveying unit 11, a second conveying unit 13, a cutter 15, a first top conveying unit 17, and a second top conveying unit 19. The first conveying unit 11 and the second conveying unit 13 define therebetween a gap 12. The cutter 15 is disposed above the gap 12.
The first conveying unit 11 is adapted to deliver a stack of toilet tissue paper 14 to the second conveying unit 13. The cutter 15 is movable across the gap 12 to cut off the stack of toilet tissue paper 14 subject to the desired length.
Normally, a toilet paper roll has a fixed shape and can be conveniently cut by the aforesaid conventional web product cutting machine 10. However, when operating the aforesaid conventional web product cutting machine 10 to cut off a stack of flat or interfold toilet tissue paper 14, the variable shape of the flat or interfold toilet tissue paper 14 will cause following some problems. As shown in FIG. 2, the stack of flat or interfold toilet tissue paper 14 consists of multiple flat or interfolded toilet tissue paper sheets 142, and its shape is highly variable.
During operation, the web product cutting machine 10 is controlled to cut the toilet tissue paper 14 into a head cut piece 141, a tail cut piece 143 and multiple normal cut pieces 145. The length L1 of the head cut piece 141 and the length L2 of the tail cut piece 143 are shorter than the length L3 of the normal cut pieces 145. Further, the length L1 of the head cut piece 141 and the length L2 of the tail cut piece 143 may be smaller than the height H of the toilet tissue paper 14. During delivery of the head cut piece 141 and the tail cut piece 143 by the first conveying unit 11 and/or the second conveying unit 13, the head cut piece 141 and the tail cut piece 143 may fall down and can be spread over the first conveying unit 11 and/or the second conveying unit 13, disturbing further screening of the head cut piece 141 and the tail cut piece 143.
To eliminate the aforesaid problem, a toilet web paper manufacturer may pack or wrap the toilet tissue paper 14 before cutting, so that the head cut piece 141 and the tail cut piece 143 can be kept in shape after cutting, avoiding spreading of the head cut piece 141 and the tail cut piece 143 over the first conveying unit 11 and/or the second conveying unit 13. However, packing or wrapping the toilet tissue paper 14 before cutting complicates the fabrication of the toilet tissue paper and relatively increases the manufacturing cost.
Referring to FIG. 3, some manufacturers may control the total length L of each stack of flat or interfold toilet tissue paper 14 to be cut and the length L3 of the desired normal cut pieces 145, keeping the total length L of each stack of flat or interfold toilet tissue paper 14 to be an integer multiple of the length L3 of the desired normal cut pieces 145, and avoiding the production of any head cut piece 141 or tail cut piece 143. After the stack of flat or interfold toilet tissue paper 14 is cut into multiple normal cut pieces 145, the first normal cut piece 147 and the last normal cut piece 149 will have an uncut edge 144 that is not cut by the cutter 15. This uncut edge 144 may cause a poor quality problem, for example, the problem of poor stacking.
Further, the length of the first normal cut piece 147 and the length of the last normal cut piece 149 may be insufficient. If the length of the first normal cut piece 147 or the length of the last normal cut piece 149 are insufficient, the first normal cut piece 147 or the last normal cut piece 149 will be unable to meet the product specifications, increasing the product of waste during fabrication.